Multicast media streamer?

So to preface the topic, I have multimedia/plexmediaserver and I love it. Its the best thing since sliced bread, and girls. :p But its a multi-stream unicast platform designed for the home user.

I did some searching on here and on the www but no joy. I am interested in setting up a mulitcast media streamer, complete with web user front. Anyone remember streamsicle from days gone by? Shoutcast? So something like those combined, but supports the option for multicast. I looked at Icecast, but I don't see that mulitcast is supported.

The envisioned use case is at any given time, dozens of genre streams are playing, and at anytime a user can 'join' the stream by using a supported multicast receiving client like VLC Player for example. Just like shoutcast a user would click on the stream they want to receive, and presto media starts flowing. Why multicast? Because some office environments (and I didn't say mine) support employees listening to music while working, and a multicast server would be just the ticket. The network (assuming they have the right gear) can be configured for PIM sparse-mode, with LAN IGMP optimizations.

So is/are there existing ports that can be recommended for me to try? Can multimedia/vlc be configured to do this, and provide that Shoutcast like use?

As always, thanks in advance,
Shoutcast still exists in the ports - audio/shoutcast. I run it on a small 256MB ram 8GB HD FreeBSD 11 vm. It's version 2.4.7.